Single counterbalanced marine loading arm



United States Patent [72] Inventor Peter .I. Bily Sunset Beach. Calif. [21] Appl. No. 735,877 [22] Filed June 10, I968 [45] Patented Dec. 15, 1970 [73] Assignee FMC Corporation San Jose, Calif. a corporation of Delaware [54] SINGLE COUNTERBALANCED MARINE LOADING ARM 1 I Claims, 10 Drawing Figs.

[52] [1.8. CI 137/615 [51] Int. Cl F161 3/00 [50] Field ol'Search 137/615 [56] References Cited UNITED STATES PATENTS 3,221,772 12/1965 Arntzen 137/615 3,236,259 2/1966 Ashton 137/615 FOREIGN PATENTS 918,575 2/1963 GreatBritain 1,369,689 11/1964 France ABSTRACT: A fluid-transferring apparatus of the marineloading arm type, including a vertical riser section, an inboard arm section mounted on the riser section for pivotal movement in a vertical plane about a first horizontal axis and in a horizontal plane about a vertical axis, an outboard arm section connected to the inboard section for pivotal movement in a vertical plane about a second horizontal axis, a single-counterweight pantograph-type counterbalance system for counterbalancing the inboard and outboard arm sections about the first horizontal axis and the outboard arm section about the second horizontal axis, and a power system for maneuvering the arm about the horizontal and vertical axes.

PATENTED DEC] 5 I970 SHEET 1 OF 5 INVENTOR. PETER J. BILY BYW ATTORNEYS PATENTED DEC 1 519m SHEET 2 [IF 5 W INVENTOR. F PETER J. aux

BY Ju a ATTORNEYS PATENTEU m1 51970 I W u m 5 3,547,153

INVENTOR. PETER J. BILY ATTORNEYS PATENTED DEC] 5 I970 SHEET 5 OF 5 INVENTOR. PETER J. BILY FIE3 B ATTORNEYS SINGLE COUNTERBALAN CED MARINE LOADING ARM BACKGROUND OF THE INVENTION The field of art to which the present invention pertains includes marine-loading arms for transferring fluid between a wharf and a vessel floating alongside, such as a cargo of petroleum or petroleum products into or from a marine tanker. In a more specific sense, the present invention involves that field of art disclosing single-counterbalanced marineloading arms provided with a power system for maneuvering the arm about horizontal and vertical axes, and for moving the counterweight to maintain the arm in balance in all its positions.

The advent of marine supertankers of 100,000 dead weight tons or more for transporting petroleum and other fluid cargoes has created a demand for greater speed and efficiency in loading and unloading these vessels in order to keep their wharfside time at a minimum. Marine-loading arms, generally comprising a plurality of rigid tubular conduits pivotally interconnected by swivel joints and mounted on an upright riser conduit on a wharf or pier, have been found most suitable for this purpose, and in order to reach the manifolds on these huge vessels and transfer the greatest volume of fluid in the shortest possible time these arms are being constructed with reaches of 65 feet and greater, and with fluidconduits of 16 or more inches in diameter. Since the boom sections of these huge loading arms can weight as much as 30 tons, they must be counterbalanced on the riser so that they can be maneuvered. One mechanism for this purpose involves a counterweight supported on the rearward end of a beam pivotally mounted above and generally parallel to the inboard section of the arm, and a system of hydraulically-operated cylinders for moving the arm and the counterweight to maintain a state of balance regardless of the position in which the arm is placed.

Although loading arms of this type have many desirable features, they also possess some that are undesirable, one being that of restricted reach especially in a generally vertical direction. The hydraulic cylinders for raising and lowering the arm commonly are connected directly to the riser in such a way that vertical movement of the arm is limited by the stroke of the cylinders. In order to elevate the coupling end of the arm sufficiently to go aboard high-sided tankers, the arm has been mounted upon a very tall riser, thereby placing the center of gravity further from the wharf and increasing the structural strength requirements for a stable, safe mounting. The counterweight on these arms also can present a restriction on their vertical reach, for when mounted in its usual position in the same plane with the riser it will not pass by that riser as the arm approaches a vertical attitude.

Another problem with the single-counterweighted loading arms of the prior art is that in their stowed position they still project forward quite a distance from their mounting. Because they must be retractible at least to the side of the wharf so as not to be in the vessel's way, these arms have to be mounted a considerable distance behind the wharfs side. Since every bit of the arms reach normally is quite valuable, such a sacrifice is very undesirable.

Mounting the arm back from the side of the wharf presents another problem, namely that extra wharf space must somehow be obtained. Space on wharves is always at a premium, and acquiring extra space on an established wharf is therefore expensive, and sometimes even impossible. Even where the alternative of adding onto the wharf is structurally feasible, it can run up the cost of the loading arm installation to an economically impractical level.

SUMMARY OF THE INVENTION The present invention solves the foregoing problems associated with powered single-counterweighted marine-loading arms by locating the counterweight and its supporting structure, and the hydraulic power system for maneuvering the arm, such that the arm can be tilted back behind the vertical into a stowed position that occupies a minimum of wharf space and thereby facilitates mounting the arm unusually close to the wharfs edge. The counterweight is split into two equal units and supported by a forked beam, one unit on each prong of the fork, so that when the arm is elevated and tilted back behind the vertical the counterweight units pass on either side of the riser. The fulcrums of a pair of bellcrank links are rotatably and coaxially mounted on opposite sides of the riser, and the forks of the beam are pivotally mounted on the first arms of the links. A first hydraulic cylinder is connected between the links first arms and a point on the beam intermediate the beams mounting on the links and the counterweight, and a second hydraulic cylinder interconnects the links second arms and the front of the riser, to provide power for pivoting the arm about a horizontal axis. Third and fourth hydraulic cylinders are mounted vertically on the front of the riser above its swivel, and a cable extending between the cylinder rods wraps around the riser below the swivel, to facilitate slewing or rotating the arm about a vertical axis.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a view in perspective of a partially extended loading arm embodying the principles of the instant invention, viewing the arm from the front and a position to the left of center.

FIG. 2 is a view in side elevation of the inner portion of the inboard arm section of the loading arm of FIG. I, and on a slightly enlarged scale, showing it in stowed position tilted behind the vertical, and in phantom lines the same position as in FIG. 1.

FIG. 3 is an enlarged fragmentary view in front elevation of the upper portion of the riser and the inner portion of the inboard section of the arm, with the inboard section extending vertically.

FIG. 4 is a fragmentary view in rear elevation similar to FIG. 3.

FIG. 5 is an enlarged fragmentary view in vertical section through the riser and the loading arms trunnion swivel, with the inboard section of the arm disposed horizontally and extending away from the viewer.

FIG. 6 is an enlarged fragmentary plan view of the upper portion of the loading arm at the juncture of the inboard and outboard sections, viewed in the direction of the arrow 6 of FIG. 1.

FIG. 7 is a side elevation of the upper portion of the loading arm viewed along the lines 7-7 of FIG. 6.

FIG. 8 is a side elevation of the loading arm, on a reduced scale, illustrating its stowed position.

FIG. 9 is a side elevation like FIG. 8, showing the arm after it has been pivoted forward from the FIG. 8 position by retraction of the rod of the front hydraulic cylinder.

FIG. 10 is a side elevation like FIGS. 8 and 9, showing the arms position after the rear hydraulic cylinderTs rod has been extended from the FIG. 8 position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Broadly considered, and as best illustrated in FIGS. I, 8, 9 and 10, the marine-loading arm 20 of this invention comprises a relatively short, upright riser 22, an inboard arm section 24 mounted on the riser for rotation about a horizontal axis X, an outboard arm section 26 connected to the inboard arm section 24 for rotation with respect thereto about a generally horizontal axis Y, a coupling assembly 28 on the other end of the inboard section 26 for connecting the arm to a marine tanker manifold, a counterbalancing assembly 30 for counterbalancing the inboard and outboard arm sections 24, 26 and the assembly 30 itself about the axis X, and the outboard arm section 26 about the axis Y, and a power assembly 32 for maneuvering the arm between a stowed position (FIG. 8) and. any position extended therefrom within the arms reach as well as through the riser 22.

Theriser 22 normally is mounted vertically and rigidly on a wharf 34 in fluid communication with a pipe line 36 extending l g to a reservoir or other fluid storage or source (not shown). As i seen best in FIG. 5, the riser22 comprises a lower nonrotatable section 38 surmounted by anupper section 40 rotatable with respect to section 38 about the vertical axis Z by virtue of their swivel joint connection 42. In the conventional manner, a fluidtight seal is established between the male and .female elements of the swivel joint 42 by a packing 44, held in place T by a retaining ring 46.

The inboard arm section '24 is mounted on the risers upper If section 40 for rotation about the horizontal axis X by means of a trunnion-swivell48, as best illustrated in FIG. 5. Because of the arms large size and weight, a bracing structure is rigidly connected to the inner arm section 24, and it is likewise mounted for rotation about the axis X on the risers upper sec- 1 F tion 40 by another trunnion swivel 52 coaxial with the swivel j 48. The bracing structure 50 provides lateral support for the -"arm '24 and helps to reduce wear on the trunnion swivel 48. Thus,-the upper section 40 of the riser 22 is shaped. generally In the conventional manner, the outboard arm section 26 is connected to the inboard arm section 24 by means of a swivel j joint 54 facilitating rotation of the outboard arm 26 about the axis Y.

The coupling assembly 28 can be of any suitable type, ini cluding the conventional style illustrated in the drawings comi ffprising an elbow 56 connected'by a swivel joint 58 to first elbow 60 on the outer end'of the outboard arm section .26, a psecond elbow 62 connected to thefirs t elbow 56 by a swivel 9 joint, and a terminal flange section-66 connected to'the second elbow 62 by swivel joint 68 for coupling the arm to the ;manifold of a tanker or other marine vessel.

T-he counterbalancing assembly 30 comprises a beam 70, a i'pair of bellcrank links 72, 74 that are rotatably mounted at ltheir fulcrums on the riser's upper section 40 through swivel joints 76, 78 (FIG. 5), a link (FIGS. 1, 6 and 7) rigidly attached to the outboard arm section 26 and rotatable with respect to the inboard arm section '24 through the swivel joint I 54, and a counterweight 82. I ,5 The beam 70 forks into two prongs or sections 70a, 70b, and these sections are interconnected and braced by longitudinal and transverse struts 86. The. sections 70a, 70b are pivotally attached to corresponding arms 72a, 74a of the bellcrank links 72, 74 at positions 88, (FIG. 5), and in the illustrated embodiment extend forward and pivotally connect to the link 80 i {at position 92. The counterweight 82 for counterbalancing the loading arm about the axis X is split into two sections 82a, 82b of equal weight, and these sections are mounted separately on the rear of the beam sections 70a, 70b.

Thus, the counterbalancing assembly 30 is pivotally ounted on the riser 22 independently of the inboard arm section 24, and also is pivotally connected to the inner end of the ms outboard section 26, so that as the outboard section 26 vots about the axis Y the beam 70 will move longitudinally and transversely with respect to the arms inboard section 24. urthermore, the forked beam 70 and split counterweight 82 nable the inboard arm section 24 to be'pivoted about the axis into a position tilted back behind the vertical (FIGS. 2 and a position that is more compact for'stowage, than one that vertical or slightly forward therefrom to which other arms e restricted. The power assembly32includes a vertical rotation unit r. rotating the inboard arm section 24 about the axis X and e outboard arm section about the axis Y, and a horizontal L tation unit 102 for rotating or slewing the arm horizontally bout the vertical axis Z. V

The vertical'rotation, unit 100 comprises a front cylinder 04 pivotally mounted at position 106 on a bracket 108 that is rigidly fixed to the risers upper section 40, and-a rear cylinder 110 that is pivotally mounted on the beam sections 70a. 70b at positions 112, 113 intermediate the counterweight and the positions 88, 90.. As seen best in FIG. 4, the piston rod 114 of the cylinder 104 is pivotally connected at position 116 to a transverse strut 118 that is fixed to the arms 72!), 74b of the bellcrank links 72; 74. In a similar manner seen best in FIG. 4, the piston rod 120 of the rear cylinder 110 is pivotally connected at position 122 to a strut 124 fixed to the arms 72a, 74a of the bellcrank links 72, 74.

When only the front cylinder.104 is operated to extend or retract the rod 114, the inboard and outboard sections 24, 26 and the counterbalancingassembly 30 rotate as a unit about Lthe riser 122* through-swivels48, .52, yet during this rotation they retain their respective positions with regard to each other, i.e;-, the angle between the inboard and outboard arm sections 24 and 26does not change and the beam 70 does not move with respect to the inboard arm section 24. For example, starting from the stowed position shown in FIG. 8, the arm will move to the position indicated in FIG. 9 when the piston rod 114 is retracted into the cylinder 104.

When only the rear .cylinder 110 is'operated to extend or retract its rod 120, the inboard arm section 24 is rotated about the riser 22through the swivels 48, 52, the beam 70 is moved longitudinally and transversely with respect to the inboard section 24 thereby pivoting on the bellcrank links 72, 74 at positions 88, 90, respectively, and on the link 80 at position 92, and the outboard arm section 26 changes its angular relation with respect to theinboard section 24. An illustration of this change from a stowed position is shown in FIGS. 8 and 10.

Therefore, by operating the front cylinder I04 and the rear cylinder 110; stepwise or simultaneously, the arm and the coupling assembly 28 can bemaneuvered vertically into any upright position within the reach of the apparatus.

This unique orientation ofthe bellcrank links 72, 74, and the likewise-unique arrangement of the cylinders 104, 110, facilitate tilting the inboard arm section 24 behind the vertical into-the more desired storage position as previously mentioned, a feature not present in other arms of this type.

The horizontal rotation unit 102 comprisesa pair of vertically mounted cylinders 130, 132 (FIG. 3) pivotally con nected to brackets 134,136 that are mounted on the risers upper section 40. Downward extensions 138, I40 of v the brackets 134,136 provide support for a pair of sheaves 142. 144 rotatably mounted on the lower ends of these extensions.

' A cable l46.is trainedaround a guide rim 148 surrounding and fastened to the risers lower nonrotatable section 38, and the ends of the cable are connected to the cylinders piston rods 150, 152. Thus, by retracting the piston rod 150 into the cylinder and simultaneously extending the rod 152 from the cylinder 132, the loading arm can be rotated clockwise about the axis Z when viewed from above, and by extending the rod and retractingthe rod 152 a counterclockwise rotation of the arm canbe achieved. This facilitates maneuvering the arm andthe coupling assembly horizontally into any lateral position withthe reach of the apparatus.

. Accordingly, it can be seen that the herein described unique system for counterbalancingand maneuvering a marine-loading arm enables the arms coupling. assembly to be positioned at any desired location within its reach capabilities, without any restriction whatsoever, while also enabling the arm to be stowed in a minimum of wharf space and tube mounted. unusually close to the' 'wharf's edge with no danger of creating an obstruction to vessels moored alongside.

1 Although the best modev contemplated for carrying out the; present invention has. been herein shown and described, it will. be apparent that modification and variation may be made without departing from what is regarded to be the subject matter of the invention as set forth in the appended claims.

I claim: 1. A fluid-transferring apparatus, comprising an inboard section mounted; upon an upright support for pivotal move ment thereon about a'first generally horizontal axis; anoutboard-armsection'pivotally connected at one end to theouter end of the inboard arm section for movement thereon about a second generally horizontal axis; a beam extending along the inboard-arm section; means pivotally connecting one end of the beam to said outboard-arm section; link means rotatably mounted on said support for pivotal movement about said first generally horizontal axis independently of said inboard-arm section; means pivotally connecting the beam to said link means; a counterweight mounted on said beam at a position to counterbalance the combined weight of said inboard and outboard arm sections and said beam about said first horizontal axis; first power means extending between said link means and said support for pivoting said link means about said first horizontal axis; and second power means extending between said link means and said beam to pivot said beam with respect to said link means and said outboard-arm-section; whereby operation of said first power means while restricting said second power means against operation causes said inboardarrn section to pivot about said first horizontal axis.

2. The apparatus of claim 1 wherein when said first power means is operated and said second power means is restricted against operation said inboard and outboard arm sections and said beam pivot as a unit about said first horizontal axis, and when said second power means is operated and said first power means is restricted against operation said inboard-arm section is pivoted about said first horizontal axis, said beam moves longitudinally of said inboard-arm section, and said outboard-arm section changes its angular relation with respect to said inboard arm section.

3. The apparatus of claim 1 wherein said link means comprises a bellcrank member with its fulcrum pivotally connected to said support 4. The apparatus of claim 3 wherein said first power means is pivotally connected to a first arm of said bellcrank member. and said second power means is pivotally connected to a second arm of said bellcrank member.

5. The apparatus of claim 3 wherein said beam is pivotally connected to one arm of said bellcrank member.

6. The apparatus of claim 1 wherein said first power means is on the opposite side of said first horizontal axis with respect to said counterweight when said inboard-arm section is in a generally horizontal position.

7. The apparatus of claim 1 wherein said second power means is pivotally connected to said beam intermediate said counterweight and said link means.

v8. The apparatus of claim 1 wherein said beam is forked into two prongs, and said counterweight comprises a pair of substantially equal weights each mounted on a separate prong of said beam and positioned to bypass said support.

9. The apparatus of claim 1 wherein said inboard-arm section, said beam, said pivotally connecting means, and said link means together define a pantograph system.

10. A fluid-transferring apparatus, comprising an inboardarm section mounted upon an upright support for pivotal movement thereon about a first generally horizontal axis; an outboard-arm section pivotally connected at one end to the outer end of the inboard-arm section for movement thereon about a second generally horizontal axis; a beam extending along the inboard-arm section; means pivotally connecting the beam to said outboard-arm section; means mounting the beam on said support for pivotal movement about said first generally horizontal axis independently of said inboard-arm section; a counterweight mounted on said beam at a position to counterbalance the weight of said inboard and outboard arm sections and said beam about said first horizontal axis; first power means extending between said mounting means and said support for pivoting said mounting means about said first horizontal axis; said first power means located on the opposite side of said first horizontal axis with respect to said counterweight when said inboard-arm section is in a generally horizontal position; and second power means extending between said mounting means and said beam to pivot saidbeam with respect to said mounting means and said outboard-arm section; whereby said inboard-arm section can be pivotedabout said first horizontal axis back behind a vertical position to facilitate compact stowage of said apparatus in a minimum of space.

11. A fluid transferring apparatus, comprising an inboardarm section mounted upon an upright support for pivotal movement thereon about a first generally horizontal axis; an outboard-arm section pivotally connected at one end to the outer end of the inboard-arm section for movement thereon about a second generally horizontal axis; a beam extending along the inboard-arm section; means pivotally connecting the beam to said outboard-arm section; means mounting the beam on said support for pivotal movement about said first generally horizontal axis independently of said inboard-arm section; a counterweight mounted on said beam at a position to counterbalance the weight of said inboard and outboard arm sections and said beam about said first horizontal axis; first power means extending between said mounting means and said support for pivoting said mounting means about said first horizontal axis; and second power means extending between said mounting means and said beam to pivot said beam with respect to said mounting means and said outboard-arm section, said second power means being pivotally connected to said beam intermediate said counterweight and said mounting means; whereby said inboard-arm section can be pivoted about said first horizontal axis back behind a vertical position to facilitate compact stowage of said apparatusin a minimum of space.

Po-wso UNITED STAT PATENT OFFICE CERTIFICATE OF CORRECTION Patent: I15. 3,547,153 Dated Dec 15, 1370 Inventorts) Peter J. Bi1y It is certified that error appears in the above-identified paten and that said Letters Patent are hereby corrected as shown below:

Column 1, line 28 change "wei ht" to "wei h Column line 38 change "storage" to stowage Column 4, lin after "inboard insert ar'm Signed and sealed this 28th day of j-December 1 971 (SEAL) Attest:

EDWARD M.FLEICHER,JR. ROBERT GOTTSCRALK Attesting Officer Acting Commissioner of Peter 

